Signaling system



March 22, E ET AL 1,850,858

SIGNA'LING SYSTEM Filed.Ju1y 9, 1928 Fig).

2 Sheets-Sheet l bum- - WWI" Inventor's Lgcur' us WRichar-dson,

Their" Attor-ne y.

March 22, 1932. R w ET L 1,850,858

SIGNALING SYSTEM Filed July 9, 1928 2 Sheets-Sheet 2 Irvin R. Weir, Lycur'gus W.Richar'dson,

5 W weal,

Their- Attorney.

Patented Mar. 22, 1932 UETD STATES rarawr Fries IRVIN R. WEIR, OF SOT-IENECTADY, AND LYCURGUS W. RICHARDSON, OF SCOTIA, NEW

YORK, ASSIGNORS TO GENERAL ELECTRIC COMPANY,

YORK

A CORPORATION OF NEW SIGNALING SYSTEM Application filed July 9,

Our invention relates to high frequency signaling systems and especially to high frequency systems for operation at short wave lengths. Still more particularly our invention relates to amplifiers which are adapted for use in systems for the transmission of lar e amounts of power at short wave lengths and it deals more specifically with the mechanical construction and assembly of the apparatus comprising the amplifier circuit.

Some of the greater difiiculties encountered in the construction of transmitting systems for operation at short wave lengths have been found to reside in the mechanical structure and assembly of the apparatus comprising the transmitting circuit. The circuits themselves, in many instances, may be those used in systems which operate at long wave lengths and hence no additional difiiculties are encountered in connection therewith. However. at the shorter wave lengths, as for example at wave lengths less than a hundred meters the effect of capacity existing in and between the dilferent components of the circuit and between the components of the circuit and surrounding objects, as well as the inductance of the necessary conducting leads and the like, lead to disturbances and difficulties which necessitate special consideration to the mechanical structure and assembly of the apparatus.

Our invention relates more particularly to the mechanical structure and arrangement of a power amplifier of the push pull type and it has for one of its purposes to provide an amplifier of the type indicated in which the efiect of stray capacity and inductance is reduced to an extent which is believed not heretofore to have been attained. A further purpose of our invention is to provide an amplifier of the type indicated which is characterized by compactness of the amplifier unit to an extent which in a large measure eliminates connecting leads between the various circuit components. Still a further purpose of our invention is to provide means whereby variations in the constants of certain elements of the circuit will not afiect the constants of other elements.

Our invention relates further to the structure of the inductance coil which may be utilized as the input coil for an amplifier of the type indicated and which possesses advantages both within itself and in connection with a system of the type to be described.

The novel features of our invention will be set forth with particularity in the appended claims. Our invention itself however, both as to its organization and method of operation, together with further objects and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying drawings in which 1 represents a side View of an amplifier constructed in accordance with our invention; Fig. 2 represents a side view, at right angles to the view shown in Fig. 1, of a portion of the apparatus shown in Fig. 1; Fig. 3 represents a detail; Fig. 4 represents a plan view, partly in section, of the apparatus and Fig. 5 represents diagrammatically the circuit of which the apparatus represented in Figs. 1, 2 and 4: is an embodiment.

Referring particularly to Fig. 1 f the drawings, 1 and 2 represent electron discharge devices which are employed in the amplifier to be described. These devices may be of any suitable construction well-l nown in the art. The lower portion of these devices comprising tne anode, is surrounded by suitable water cooling jackets 3 and 4 respectively. These discharge devices are arranged upon opposite sides of the center of the interior of the conducting housing 6 in w iich our apparatus is enclosed and are arranged symmetrically with respect to the side walls thereof. Located between the discharge devices is an input inductance coil 5 which is supported in suitable manner as from the top of the housing 6 by members 6. Upon opposite sides of the coil 5 are contact members 7 and 8 which are connected to the grids of each of the discharge devices by means of conductors 9 and 10. Located below the inductance coil 5, and also between the discharge devices is a second inductance coil 11. This inductance coil is of high current carrying capacity and preferably is comprised of water cooled conducting tubing having opposite terminals thereof'connected to the water cooling jackets 3 and 4 of. the discharge devices 1 and 2 through suitable conducting water connections 12 and 13. Since the anodes of the discharge devices 1 and 2 which comprise cylindrical members 16, as shown in Fig. 3 and which are arranged within the water jackets 3, or 4;, are electrically connected to the water jacket, both through the water and at the point 17, it will be seen that these water cooling jackets and the conducting members which are connected thereto, including the coil 11, are all maintained at the potential of the anodes.

The water cooling circuit of the coil 11 extends from the input pipe 12 of the jacket 3 through the connections 14 and coil 11 to the output pipe 13 leading from the jacket 4. The water cooling circuit of the discharge devices 1, of which there may be a plurality and which is similar to that of the discharge devices 2 is best shown in Fig. 2. This cooling circuit is shown as extending through the input pipe 12 of the cooling ackets 3 and 4 in series to the output pipe 13. It will, of course, be understood that any suitable cooling system may be employed.

Mounted upon the side walls of the water jackets 3 and 1, by means not shown, and preferably upon opposite sides thereof from the inductance coils 5 and 11 are parallel plates 18 which are best shown at the right side of Fig. 1, and in Fig. 4. These plates are suitably supported from the base of thehousing 6 by supports 19 which are suitably insulated from the base. Between these conducting plates are mounted neutralizing capacitors 20 and 21, the capacitor 20 beingrepresented in dotted lines in Fig. 1. The stationary plates 22 of these capacitors are supported from an insulating member 23 which in turn is supported by means of a member 21, extending between the upper portions of the plates 18. The plates 22 of the capacitor 20 are electrically connected by conductor 25 to the grid connection 9 of the electron discharge device 1, and the corresponding plates of the capacitor 21 are connected by means of conductor 26 to the grid connection 10 of the discharge device 2. The purpose of the plates 18, as will later be indicated, is to provide a shield about the neutralizing capacitors which are included therebetween and accordingly the. outer plate 18 is shaped to enclose the capacitor and further is extended about the water coolshafts 28 are adapted for rotation by any suitable means such as worm gears 29 and shaft 30 which are controlled from the front of the panel, which comprises one of the side walls of the housing 6.

lVith the apparatus as thus arranged it will be seenthat the grids of the electron dis charge devices 1 and 2 are connected together through the inductance coil 5 and that their anodes are connected together through the inductance coil 11. This circuit arrangement is better illustrated in Fig. 5. The anode circuit of the electron'discharge devices 1 and 2 is energized by means of a source of potential 31, the negative side of which is connected to the cathode of the electron discharge devices 1 and 2 and to the side walls of the housing 6. The positive side of this source of potential is connected to the midpoint of the coil 11. Likewise a suitable source 32- of biasing potential for the grids of the electron discharge devices is connected between the housing 6 and the midpointof the coil 5 through which it is connected to the grids of the electron discharge devices 1' and 2. The neutralizing capacitors 20 and 21 are connected by means including conductors 25 and 26, respectively between the anode of one of the discharge devices 1 and 2, and

the grid of the opposite discharge device. It

will thus be seen that a conventional pushpull circuit with. neutralizing capacitors is provided.

With the apparatus as arranged in Fig. 1 it will be seen that a certain distributed ca pacity exists between the anodes of the devices 1 and 2 this capacity including such stray capacity as exists between theelements which are directly connected to theanodes of one device and those directly connected to the anodes of the other and such capacity as. exists between these elements and other surrounding objects comprising principally the housing 6. ln order that equal capacity will exist between each of the discharge devices and the housing the discharge devices are located symmetrically with respect to the side walls of the housing and upon opposite sides of the center thereof. These capacities are, of course, in shunt relation with the coil 11. a

To vary the frequency at which the system is adapted to operate conducting bodies," or plates 33 and 3-1 are provided. These plates are supported from, and are conductively connected to, the housing 6 by means of a shaft 35. This shaft is adapted for rotation by means of a shaft 36 which extends through the panel and which is connected by means of worm gears 37 to the shaft 35. These plates have a large conducting surface and may be rotated into proximity with the plates 18, in which case, a large capacity will exist between the plates 18 and the conducting bodies 33 and 34. Likewise these plates may be rotated in the opposite direction until very small capacity exists between the plates 33 and 34 and the plates 18, in which case the length at which the output circuit is tuned to operate.

The necessity for the conducting plates 18 will now be apparent. t will be seen that he stationary plates 22 of the neutralizing capacitors are at the potential of the grid whereas the movable plates 27 thereof are at the potential of the anode. Thus a large difference or" potential exists between the m vable plates and the fixed plates with the result that these plates must be supported at considerable distance apart. Hence in order that the capacity between these plates be varied to the extent desired, it is necessary that a considerable range of movement for the movable plates 27 be provided. l Vere it not for the plates 18, changes in the position of the movable plates 27 would vary the capacity existing between the housing 6 and the v high potential members of the transmitting apparatus and the frequency at which the output circuit is tuned to operate would be changed. This diiiiculty is obviated by enclosing these capacitors with the plates 18.

While we have shown the neutralizing capacitors mounted between the discharge devices and the iousing it will of course be understood that they may be mounted upon either side of the discharge devices. It is desirable however that they be mounted directly upon the water jackets and that the shielding plates 18 be utilized for the purpose stated.

If no neutralizing capacitors were to be employed then the plates 18 and the structure enclosed thereby might be eliminated, the plates 33 and 34 then being adjustable between the water jackets of the electron discharge devices and the housing, or if no water jackets are employed then between the anodes or" the discharge devices themselves and he housing. However, the external capacity existing between the anodes of the discharge devices and the cathodes and the range of frequencies over which the system is adapted to operate may be increased if one of the plates 18 be mounted against the side walls of the water jackets, or discharge devices and the plates 33 and 34 arranged for movement in proximity thereto.

In cooperation with the tuning means as thus far described an additional tuning means comprising a substantially circular member 38, such as an annular body, or disk, arranged for rotation within the coil 11, is

provided. This member which may be comprised of any suitable conducting material, such as copper, or aluminum, is spaced from the coil 11 and has a diameter somewhat less than the inner diameter of the coil. In efiect it constitutes a short circuited turn mounted within the coil and as such it produces varying effects upon the coil in different positions in rotation. Thus the inductance of the coil may be varied by rotating this member. Of course the tuning effect of this member increases as the inductance of coil 11 decreases. Hence this member is a very desirable means for tuning purposes when the set is operated at short wave lengths as when a portion of each end of the coil is short circuited by the short circuiting switches 75 and 76. These switches are mounted in any suitable manner and are adapted by flexible leads to short circuit any desired portion of the coil. At the longer wave lengths these switches are opened and the necessary tuning within a desired range is effected by the plates 33 and 34.

It will be apparent that if the system is to operate continuously at short wave lengths the plates 33 and 3st may be removed and the member 38 may be relied upon for the necessary tuning. At these wave lengths the input coil may be of a construction similar to the output coil shown. By utilizing both of these tuning means described however the system is adapted for operation over a very broad range of frequencies and the tuning is readily variable in all parts of the range, the member 38 being the more etlective at the shorter wave lengths and the plates 33 and 34 being the more etl'ective at the longer wave lengths.

A further understanding of the assembly of the apparatus may be had by reference to Fig. at in which a plan view of the apparatus partly in section is illustrated. It will be seen from this figure that contacts 7 and 8 on the coil 5, which contacts are connected to the grids of devices 1 and 2, are located upon opposite sides of the coil midway of the length thereof, and also that these contacts are located about midway between the different devices 1 and 2. The devices 1 and 2 are arranged in their water jackets in a manner such that the grid leads 9 and 10 project radi ally toward the contacts 7 and 8, such that these leads are all of about the same length, and, th refore, have about the same distrib uted inductance and capacity. The discharge devices are also in proximity to the coil such that the leads 9 and are very short.

The coil 5 is of cylindrical construction having oppositely wound sections 39 and 4-0 extending from a conducting slip ring 41 arranged at the center of the coil. Extending axially within the coil is a shaft 4- having slip rings 43 and er arranged at the en d there of, conducting supports 45 and 46 arranged thereon and within the coil sections 39 and 40 respectively, and a control handle 47 connected to the end thereof, such that this shaft together with the supports and 46 may be rotatedv as desired. The supporting members 45 and 46 are connected to the slip rings 43 and 44 respectively through conductors 48 and 49, these conductors being mounted for. rotation with the shaft and extending through a suitable insulating bushing 50. The bushing 50 comprises a part of the mechanism whereby the shaft 42 is supported for rotation and has about it a. pair of suitable concentric bearing members 51 and 52 which are adapted for rotation with respect to each other. The bearing member 52 is supported by an additional bearing member 53 which in turn is attached to the supporting member 6. The shaft and the bearing members 51 and 52 are each rotatable with respect to the stationary bearing member 53 and the bearing members 51 and 52 are rotatable with respect to each other. The outer end of the section 39 of the coil 5 is supported by means of insulators 54 by the bearing member 52. The opposite end of the coil 5 is supported by means of insulators 55 which are securely attached to a bearing member 56. This bearing member is concentric with the shaft 42 and arranged within a concentric stationary bearing member 57 which is supported from the members 6. The bearing 56 has a handle 58 attached thereto and arranged on the front of the panel 59. By means of this handle the bearing members 56 and 52 may be rotated thereby causing the coil 5 to be rotated about the shaft42. This handle may be retained in a stationary position by means of a suitable locking device such as member 60 which is mounted thereon and which is adapted frictionally to engage the panel 59.

Arranged for slidable engagement with each of the conducting supports 45 and 46 are contacts 61 and 62, these contacts being securely attached to the supports and adapted for rotation with the shaft 42. These contacts have pair of prongs which project upon opposite sides and into engagement with one of the turns of the coil, such that as the shaft '42 is revolved the coil remaining stationary, each of the contacts 61 and 62 follows along the turn of the coil with which it is in engagement and is thereby caused to slide longitudinally of the supports 45 and 46. These contacts are spaced equally from the slip ring 41 and hence from the center of the coil, such that as the shaft 42 is revolved these contacts move in opposite directions, thereby producing equal changes in inductance between the center of the coil and the two contacts.

On the outside of the coil and extending longitudinally of each section thereof are additional conducting supports 63 and 64, these supports being connected to the grid conductors 9 and 10. Mounted upon these supports and in engagement with a turn of the coil are contacts 65 and 66, the structure of these contacts being identical with that of contacts 61 and 62. When the coil is revolved these contacts are caused to slide longitudinally of the supports 63 and 64 in opposite directions and thereby to produce equal changes in inductance between the center of the coil and the two contacts.

Connected to the slip rings 43 and 44 is a suitable source of high frequency current 67.

Suitably mounted, as by means of members 68 extending longitudinally of the coil and in engagement with the ring 41 is a brush 69 (Fig. 1). This brush is connected to the negative side of the source of potential 32 by means of conductors not shown. As thus described it will be seen that high frequency current from the source 67 may be impressed upon the coil 5, symmetrically with respect to the center thereof, and that these currents may be equally impressed upon the grids of the discharge devices 1 and 2. F or the purpose of varying the inductance of the line including the portion of the coil between the contacts 45 and 46 and the generator 67, as for the purpose of tuning the supply circuit, which may be a transmission line, the handle 47 may be rotated, thereby causing the contacts 61 and 62 to move in'opposite directions along the coil. The handle 47 may then be locked by means of the locking device 7 0 to the handle 58. By means of the handle 58, which may now be unlocked from the panel, the coil 5 and the shaft 42 carrying the contacts 61 and 62may be rotated together, causing the contacts 65 and 66 to move in opposite directions along the coil, thereby to vary in equal amounts the inductance in the two grid circuits, as for tuning purposes without efiecting the'position of contacts 61 and 62 upon the coil.

It will be apparent from the structure of the input coil as thus described that the inductance between the grid contacts, and that between the transmission line contacts may be continuously varied over a broad range and that either of them may be varied independently of the other. Further this coil comprises a compact unit which may be readily supported between the discharge devices and conveniently controlled from the front of the panel. This coil possesses the further advantage. that variations in the connections thereto do not materially affect the distributed capacity existing between it and surrounding objects.

Vhile for tuning purposes additional capacity may be connected between contacts 7 and 8 at the higher frequencies the inductance coil may be made to resonate with the internal capacity of the discharge devices in the manner well-known in the art.

With the transmitting system arranged as.

described we have found that the unit is considerably more compact than those of the prior art and that the efiect of stray capacity is materially reduced. Practically the only connecting leads employed are those connecting the grids of each of the discharge devices with the associated neutralizing capacitor the other cannectioss bani made by mechanical engagement of the elements themselves. Further by locating the coils directly between the discharge devices it has been found that the effect of distributed capacity is substantially reduced. As such the system has been found to produce large amounts of power at wave lengths which are considerably lower than those obtainable by means of the prior art.

ll hile we have shown a particular embodiment of our invention it will, of course, be understood that we do not wish to be limited thereto since many modifications may be made without departing from the spirit and scope of our invention as set forth in the ap pended claims.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. The combination, in a high frequency transmitting system, a pair of electron discharge devices having water cooling jackets, means connecting said discharge devices in push-pull relation including a tuning coil arranged in space between said discharge devices, neutralizing capacitors mounted upon said water cooling jackets having plates conductively connected thereto and each capacitor having additional plates connected to the grid of the opposite discharge device and shielding means for preventing variations in the neutralizing capacitors from effecting the tuning of the circuit including said coil.

2. The combination, in a high frequency transmitting system having a housing, a pair of electron discharge devices symmetrically arranged in space relation with reference to the side walls of said housing, means connecting said discharge devices in push-pull relation, a connection between the cathodes of said devices and this housing, and means for varying the frequency at which said system is adapted to operate comprising conducting bodies connected to the housing and movable in space between said discharge devices and the housing.

3. The combination, in a high frequency transmitting system, having a housing, a pair of electron discharge devices symmetrically arranged in space relation with reference to the side; walls of said housing, means connecting said discharge devices in push-pull relation including an output inductance coil having opposite points thereon connected to the anodes of said discharge devices, and means for varying the frequency at which said system is adapted to operate comprising a conducting body located between each of said devices and adjacent sidewalls of the housing and means connecting said conducting bodies whereby they are equally movable in space to provide equal changes in capacity between said devices and said bodies, said bodies being conductively connected to the housing.

4. The combination, in a high frequency transmitting system, having a housing, a pair of electron discharge devices, symmetrically arranged with reference to the side walls of said housing, means connecting said discharge devices in push-pull relation including an output inductance comprising a coil located between said devices and having opposition points connected to the anode thereof and means for varying the frequency at which said system is adapted to operate comprising a pair of conducting bodies movable between said devices and the adjacent side walls of the housing and a conducting disk arranged for rotation within said coil.

5. The combination, in a high frequency transmitting system, comprising a pair of electron discharge devices spaced apart and having substantially equal capacity between each device and surrounding objects, means connecting said devices in push-pull relation including an output inductance coil arranged between said devices, a pair of conducting bodies located on opposite sides of said discharge devices from said coil and arranged for equal movement with respect thereto thereby to vary the capacity in shunt with said coil, said bodies being connected to the cathodes of said devices, switching means for short circuiting a portion of said coil and a conducting member arranged for rotation within said coil to vary the inductance thereof.

6. The combination, in a high frequency transmitting system, having a housing, a pair of electron discharge devices, symmetrically arranged in space relation with reference to the side walls of said housing, means connecting said discharge devices in push-pull relation including an output inductance coil having opposite points thereon connected to the anodes of said discharge devices, neutralizing capacitors mounted upon the sides of said discharge devices, conducting shields surrounding said capacitors and conductively connected to the anodes of said devices and conducting plates connected to said housing and movable into proximity to said conducting shields whereby the frequency at which said system is adapted to operate may be varied.

7. The combination, in a high frequency transmitting system, having a housing, a pair of electron discharge devices arranged symmetrically in space relation with reference to the side walls of said housing, means connecting said discharge devices in push-pull relation comprising a pair of inductance coils mounted between said discharge devices, one

.of said coils having opposite points connected to thegrids of said devices and the other coil having opposite points connected to the anodes of said devices, means for supplying potential with respect to that of said housing to grids and anodes of said devices, and conducting bodies connected to the housing, arranged on opposite sides of said discharge devices and movable between said housing and said discharge devices thereby to vary the frequency at which said system is adapted to operate.

8. The combination, in a high frequency transmitting system, a pair of electron discharge devices, means connecting said discharge devices in push-pull relation comprising a pair of inductance coils arranged between said devices one of said coils having opposite points connected to the grids of said devices and the other coil having opposite points connected to the anodes of said devices, neutralizing capacitors mounted on opposite sides of each of said discharge devices from said coils, a shielding plate connected to said anodes and arranged on opposite sides of each of said capacitors from said dis charge devices and a pair of conducting bodies connected together and arranged for equal movement with respect to said shielding plates thereby to vary the capacitywith which said second mentioned coil is adapted to resonate. said shielding plates preventing changes in the neutralizing capacity from affecting said last mentioned capacity;

9. The combination, in a transmitting syswtralizing capacitors mounted adjacent said water jackets, each of said capacitors being connected electrically between the plate of the device on; which it is mounted and the grid of the other device, and a separate shield arranged about each of said variable neutral izing capacitors whereby variations in said capacitors are prevented from affecting the frequency at which said system operates.

' 11. The combination, in a high frequency transmitting system, a pair of electron discharge devices spaced apart, means connecting said discharge devices in push-pull relation, said means including a tuning inductance located centrally with respect to said discharge devices whereby the frequency at which the system operates may be determined, a variable neutralizing capacitor mounted adjacent the anode of each of said discharge devices, each of said capacitors being electrically connected to the anode adjacent to which it is mounted, and having a plate connected to the grid of the other device,and means for preventing variations in said capacitors from afiecting the frequency at which the system operates as determined by said tuning inductance.

In witness whereof we have hereunto set our hands this 6th day of July, 1928.

IRVIN R. WEIR. LYCURGUS W. RICHARDSON.

tem, a pair of electron discharge devices, each 7 of said devices having an anode, a cathode and a grid, means connecting said coils in push-pull relation comprising a cylindrical coil arranged between said devices, said coil having oppositely wound sections extending from .the midpoint thereof, a conducting member extending longitudinally of each section, each member being connected to the grid of one'of the discharge devices, contacts arranged for sliding engagement with said coil and said members and arranged forlongitudinal movement with respect to said member as the coil is revolved, an additional contact arranged within each section of said coil and adapted for movement both longitudinally and circumferentially thereof, a second coil arranged between said discharge devices and having opposite points connected to the anodes of said devices, and means in addition to said coils for varying the frequency at which said system is adapted to operate.

10. The combination, in a high frequency transmitting system, a pair of electron discharge devices having water cooling jackets,

means connecting said discharge devices in push-pull relation, sald means including tuning means for causingthe'system to operate 7 at a predetermined frequency, variable neu- 

